Microbiology & Antimicrobials

Question 1

name a gram positive cocci bacteria and give the colour and shape

Answer 1

s. anginosus
purple
round

Question 2

name a gram negative cocci bacteria and give the colour and shape

Answer 2

veillonella species
red / pinkish
round

Question 3

name a gram positive bacilli bacteria and give the shape

Answer 3

actinomyces israelii
rod shaped

Question 4

name a gram negative bacilli bacteria and give the shape

Answer 4

prevotella intermedia

Question 5

what does aerobic mean

Answer 5

requires oxygen

Question 6

what does capnophilic mean

Answer 6

requires carbon dioxide

Question 7

what does facultative mean

Answer 7

can grow with and without oxygen

Question 8

what does strictly anaerobic mean

Answer 8

grows without oxygen
oxygen might even be toxic for these bacteria

Question 9

what antibiotic works on strict anerobes

Answer 9

metronidazole only

Question 10

how does antimicrobial resistance occur

Answer 10

occurs when microorganisms such as bacteria, viruses, fungi and parasites change in ways that render the medications used to cure the infections they cause ineffective

Question 11

what are the 2 types of resistance

Answer 11

intrinsic resistance

acquired resistance
- mutation
- acquisition of new DNA

Question 12

name mechanisms of antibiotic resistance

Answer 12

changes to the target site (binding proteins of the antibiotics no longer able to bind to the bacteria)

enzymatic inactivation (enzymes destroy antibiotics or prevent binding to target sites eg beta lactamase enzyme destroys the antibiotic)

decreased uptake

Question 13

what is an endogenous infection

Answer 13

= bacteria thought to originate from our own endogenous flora (minority)
As opposed to the exogenous type of infections you can get from classic pathogens such as staphoreous (although some people believe you can get cross infection from certain organisms in the acute dental abscesses)

Question 14

give examples of bacteria found in acute dento-alveolar infections

Answer 14

streptoccus anginosus
prevotella intermedia

Question 15

what are the treatment principles of dental abscesses

Answer 15

localised infection
establish a diagnosis - need to take a good history and carry out a thorough examination
document it
remove the source of the infection

Question 16

what is the microbiology of pericoronitis

Answer 16

predominantly mixed oral anerobes eg P intermedia
S. anginosus group

Question 17

what is treatment of pericoronitis

Answer 17

local measures
antibiotics only if there is systemic signs and symptoms

Question 18

treatment of dry socket

Answer 18

does not require antibiotic treatment
treatment is under LA
Debridement
packing with antimicrobial gels or gauze strips

Question 19

what is osteomyelitis predisposed by

Answer 19

MRONJ
impaired vascularity of bone due to radiotherapy or pagets disease
foreign bodies (implants)
compound fractures - communication either intra- or extra-orally
impaired host defence - diabetes

Question 20

microbiology of osteomyelitis of the jaws

Answer 20

anaerobic gram negative rods
anerobic streptococci
streptococcus anginosus
staphylococcus aureus (any infection in the bone we worry about S. aureus infections as this affects the choice of antibiotic we can use and usually require a long course)

Question 21

microbiology of salivary gland infection

Answer 21

s. aureus
mixed anaerobes

Question 22

treatment of salivary gland infection

Answer 22

drainage
flucloxacillin and metronidazole

Question 23

what must you always do in the context of acute alveolar infections

Answer 23

1. document diagnosis following history and examination
2. document antibiotic choice, dose, route and duration
3. document a review date (for an acute infection it usually should be within 24-48 hours)
4. document deviation from guidance

Question 24

what is SOI

Answer 24

Severe odontogenic infection

Question 25

what is ludwigs angina

Answer 25

bilateral infection of the submandibular space most common bacteria: anaerobic gram negative bacilli (P. intermedia), steptococcus anginosus, anaerobic streptococci

Question 26

what is sepsis

Answer 26

infection + SIRS

Question 27

What is SIRS

Answer 27

systemic inflammatory response syndrome 2 or more of: 1. temp <36 or >38 2. pulse >90/min 3. resp rate >20/min or (PaCO2 <4.3) 5. WCC <4 or >12

Question 28

are antibiotics used to treat sepsis

Answer 28

yes the sooner you administer antibiotics the greater the chance of the patient surviving sepsis but reassess antimicrobials daily: - optimise - reduce resistance - avoid toxicity - reduce costs

Question 29

what is sepsis

Answer 29

life threatening organ dysfunction caused by dysregulated host response to infection

Question 30

what is septic shock

Answer 30

sepsis + unresponsive to fluid resuscitation subset of sepsis with circulatory and cellular / metabolic dysfunction associated with higher risk of mortality

Question 31

what are the treatment principles for SOI and ludwigs angina

Answer 31

primary care - diagnosis - seek advice / help secondary care - diagnosis - sepsis 6 - national early warning score (NEWS-2)

Question 32

what is the sepsis 6

Answer 32

1. give high flow oxygen 2. take blood cultures 3. give IV antibiotics 4. give a fluid challenge 5. measure lactate 6. measure urine output

Question 33

what is a break point

Answer 33

chosen concentration (mg/L) of an antibiotic which defines whether a species of bacteria is susceptible or resistant to the antibiotic

Question 34

what is clinical resistance

Answer 34

when infection is highly unlikely to response even to maximum doses of antibiotic

Question 35

what are confounding variables of resistance in the lab

Answer 35

- inoculum size, growth phase, planktonic, pH, atmosphere - breakpoint calling - biofilm

Question 36

what are confounding variables of resistance clinically

Answer 36

co-morbidities, pus collections, foreign bodies, site of infection biofilm pharmacokinetics pharmacodynamics

Question 37

what are pharmacokinetics

Answer 37

how antibiotics are distributed through the body

Question 38

what are pharmacodynamics

Answer 38

how the antibiotic classes interact with the bacteria

Question 39

what is antimicrobial stewardship

Answer 39

preserve antimicrobial medicines by taking measures to promote their control

Question 40

3 ways to contribute to antimicrobial stewardship

Answer 40

1. prevention of dental disease 2. prevent spread of disease (wash hands / SICPS / get vaccinated against the flu) 3. antibiotics dont cure toothache